In general, a dialysis machine is used as a substitute for the natural kidney functions of a human body. As such, the dialysis machine cleans the blood of the natural accumulation of bodily wastes by separating the wastes from the blood outside the body or extracorporeally. The separated wastes are discharged and the cleansed blood is returned to the body.
A dialysis machine uses a dialyzer to separate the wastes from the blood. The dialyzer includes a porous medium located within an enclosure which separates the dialyzer into a blood compartment and a dialysate compartment. The blood removed from the patient flows through the blood compartment, and a prepared solution of dialysate flows through the dialysate compartment. The wastes from the blood pass through the medium by osmosis, ionic transfer or fluid transport into the dialysate, and depending upon the type of dialysis treatment, desirable components from the dialysate may pass in the opposite direction through the medium into the blood. The transfer of the wastes from the blood into the dialysate cleanses the blood while allowing the desired components from the dialysate to enter the bloodstream.
Accomplishing these functions requires a number of complex systems and components. In an extracorporeal flow path, which conducts blood from the patient to the dialyzer and then back to the patient, at least one arterial blood pump and sometimes a venous blood pump move the blood and assist in performing certain types of dialysis treatment such as ultrafiltration. A hydraulics flow path, which conducts the dialysate through the dialyzer, includes numerous components to monitor and control the conditions in that flow path. Flow meters are located at the inlet and outlet of the dialyzer. One dialysate pump moves dialysate into the dialyzer, and another dialysate pump removes the dialysate from the dialyzer. Sterilant pumps deliver a predetermined amount of disinfectant into the hydraulics flow path for disinfecting the hydraulics flow path prior to the treatment. An ultrafiltration pump is used in ultrafiltration dialysis treatments to control the delivery of desirable components to the blood. A heater heats the dialysate to body temperature to avoid undesirable heat transfer to or from the patient. The heater is also used to heat the disinfecting solution to temperatures adequate to kill microorganisms. Many other equally important components are required to function properly both during treatment and to prepare the machine for use.
In addition to the individual components, the dialysis machine usually includes a control system and a safety system. The control system controls the normal operation of these components during dialysis treatments and during the preparation of the machine for the treatment. The safety system monitors the performance of these components and the functionality of the control system. If the control system functionality or components fails, the safety system assumes control and places the dialysis machine in a safe state to avoid risks to the patient.
Since all of these components are subject to mechanical wear from use, the components occasionally fail and ultimately wear out. The typical practice is to conduct regular scheduled maintenance on dialysis machines, during which some components may be replaced prior to failure or malfunction. The replacement decisions are primarily at the discretion and judgment of the maintenance personnel. Components which are not replaced during regularly scheduled maintenance intervals usually fail during dialysis treatments.
Failure during a treatment generally does not place the patient in an unsafe position because of the safety features incorporated into the safety system. The patient may experience the inconvenience of the delay in treatment while another dialysis machine is substituted, and the clinic may experience the inconvenience of adjusting the treatment schedules of patients due to the delays in treatment, thereby decreasing efficiency. One significant inconvenience associated with an equipment failure is that a special maintenance service call is normally required. Special service calls are usually more costly than regularly scheduled service calls. Perhaps a more significant consequence of component failures is the downtime during which the dialysis machine is not available for treating patients.
The cost of dialysis treatments is in some measure related to the cost of upkeep of the dialysis equipment, and the ability to make maximum use of the dialysis equipment. With the public sentiment toward reducing or containing the costs of medical care, increased maintenance costs have a direct influence on the ultimate costs of medical treatment.
These and other problems, issues and concerns have given rise to the present invention.